1. Field of the Invention
The present invention relates to circuits for driving an output load, and more particularly to drive circuits capable of achieving rapid pulldown or discharge of an output load while minimizing the output current and voltage.
2. History of the Prior Art
It is known to provide circuits for driving an output load in response to an input signal. In the case of a capacitive output load, circuits are known which pull down or discharge the capacitive output load in response to an input signal of predetermined level. Desirably, such circuits are capable of driving large amounts of current at the output load while maintaining low output voltage and low drive current. An example of a capacitive output load with which such circuits are used comprises the gate of a power MOSFET which is external to but used in conjunction with an integrated circuit.
Circuits for driving an output load in high current fashion while at the same time attempting to maintain a low output voltage and low drive current have assumed a number of different forms. One such circuit utilizes constant drive. Such circuits tend to be temperature-limited as well as subject to process variations. On the other hand, the use of a Darlington configuration provides ample current drive but suffers the disadvantage of high output voltage.
Therefore, it would be advantageous to provide a driving circuit for an output load which provides pulldown or discharge of the output load in an effective manner and without suffering from the disadvantages of high output voltage or high drive current.